Seven years ago, this blog you’re reading now was an online column offering advice on such things as traveling with a PDA in lieu of a laptop.

On that particular topic, I wrote that accessing the Internet on a PDA was like “driving cross-country in a Pinto with a cracked windshield–painfully slow and monumentally irritating.” One of the main options for checking e-mail on a handheld, I explained, was to connect the PDA to “a dial-up modem and a landline connection.”

We’ve come a long way since then, don’t you think? And I’ve thoroughly enjoyed the journey, reporting every week on the collective digital path we’ve been on. But after nearly eight years of writing Mobile Computing, this blog post is my last. It’s time for me to move along my own path. I’ll still contribute to PC World on mobile technology, social media, and other topics.

Before I log off, however, I’d like to pass along five lessons learned along the way.

1. Most GPS Devices Aren’t Worth the Money

As a portable gadget fan, I’ve bought at least one of nearly every device you can image. And yet, I’ve never purchased a portable GPS device, nor even been tempted to buy one. That’s because every GPS device I’ve ever tested has given me some whacky, if not downright convoluted, directions.

For example, an HP iPaq Travel Companion had me taking 19 different streets when I needed only five. A more recent device, the Garmin Nuvi 1370T, suggested I drive past my destination and circle back around, when all I had to do was make a legal left turn to get there.

GPS devices are getting better, of course, and they’ll continue to improve. But for now, I’ll stick with getting occasional directions via Google Maps on my iPhone (except when I’m traveling internationally, as I discussed last week in my blog on smartphone dependence. I’ll most likely get better directions, and I’ll save money and reduce the number of gadgets to pack and recharge, too.

2. Avoid Restocking Fees

These days, there are few stores where you can get hands-on time with digital cameras, laptops, and other consumer electronics. This means you may have no choice to buy a product online that you’ve never actually seen.

For this reason, it’s extra important to study an online retailer’s return policy. While you’re at it, consider the e-commerce site’s policy on restocking fees, too. Many retailers charge 15 per cent of the purchase price if you return a product for reasons other than it’s defective or the retailer made a mistake (such as sending you the wrong product). On a $1000 laptop, that means you’ve spent $150 just to give it a test drive.

I often buy from J&R because the retailer doesn’t automatically hit you with a restocking fee. Two caveats, however: Like many online retailers, J&R requires you to get a return authorization from them before returning a product. And you won’t avoid the restocking fee if you return something that’s not in as-new condition or is missing an included accessory or some original packaging material.

3. Don’t Bother Trying to Time a Tech Purchase

To avoid instant buyer’s remorse, it’s logical to try to plan your purchase of a portable device. For instance, we’ve come to expect Apple to refresh its iPod line-up in September or October. (Read Harry McCracken’s thoughtful insights into the latest iPod announcements.) Thus, to purchase an iPod in mid-late August is to ask for instant buyer’s remorse.

Nonetheless, obsessively trying to buy a new electronic device at precisely the right moment can cause madness. I know; I’ve tried and failed. A recent case in point: I waited for about 18 months before buying my first netbook,the Samsung N120. I wanted a netbook that had good battery life (at least five hours) and as comfortable a keyboard as possible. The N120 fit the bill.

However, sometime between the moment I clicked the Buy button for the netbook and the arrival of the UPS delivery guy, Toshiba came out of nowhere with the Mini NB205-N310. In a PC World review, Darren Gladstone says the

Toshiba netbook has a “killer” keyboard and ridiculously long battery life. It costs about $400, about the same as the Samsung N120. So what can you do about it? You can do your homework before making a purchase, of course. For instance, you might check the manufacturer’s press release archives online to see when the product you’re contemplating was released. The longer the product has been on the market, the greater the odds are that its cheaper-faster-better replacement, or something even better from a competitor, is waiting in the wings.

Also, try to educate yourself on what the next-generation of a product might look like and how soon it might arrive. For instance, some people will call you crazy if you buy a netbook before the new nVidia Ion platform models arrive in full force. The Ion promises to give netbooks better graphics performance. Ultimately, though, just buy the product that best meets your needs and budget; buy it when you truly need it; then move on. (By the way, I love my Samsung N120).

4. Live in the Cloud

Next March, Broadway Business, part of Random House, will publish Getting Organized in the Google Era, a book I collaborated on with Douglas C. Merrill, Google’s former CIO. The book explains how information is key to being organized. So to be better organized today, it helps to keep information that’s important to you in one centralized place (the Internet, aka “the cloud”) so you can access it anytime using a smartphone, laptop, or other device.

This advice is especially relevant for mobile professionals–and those who have more than one computer in particular.

If you use Microsoft Outlook for e-mail, for instance, you may have your messages downloaded from your ISP’s server onto to your own computer’s hard drive. But if you’re traveling with your netbook and an e-mail you need is on your computer at the office, you’re out of luck. A better idea is to use a Web-based e-mail system, such as Gmail or Zoho Mail. That way, you can get to your e-mail from any device with an Internet connection and a Web browser.

Also, because Gmail and Zoho Mail offer tons of storage, you don’t have to delete old messages to make room for new ones. This gives you another organizational benefit: When your Web-based e-mail system is backed by strong search capabilities, and you’ve got years of messages stored in it, you can turn your e-mail into a personal data archive that’s always available. Among other things, the book explains how to do this, and how it can help you be better organized.

Because we can stay constantly connected to e-mail and the Web, that’s exactly what many of us do. I mean, how often do you see someone walking down the street, their eyes focused on a little gadget in their hand? Maybe you don’t notice because your eyes are on your BlackBerry, iPhone, or whatever.

I’ve been as guilty of this as anyone else. I’m not implying that you should leave your portable electronics at home. That’s what they’re here for–to help us stay productive wherever we may be.

Recently, however, I was reminded that when you connect to the Internet on the go, you disconnect from the world around you. I believe that, cumulatively, you pay a price for those disconnects. What you’re doing is retreating from a world that will never quite be within your grasp into something much smaller that fits in the palm of your hand, something you can more easily control. There’s comfort in that, to be sure.

But is that what your goal should be–to constantly seek control or comfort? Put another way, what might happen if instead of checking your e-mail while standing in line at Starbucks, you said hello to the person behind you? The answer can’t be found on Wikipedia. However, this I know for certain: Your e-mail will still be there when you get back to the office.